Birmingham, AL Accessory Structures: ADU Rules (2026)

Alabama has no statewide ADU statute; under the municipal zoning authority granted by Title 11, Code of Alabama, ADU rules are set entirely by local ordinance. The City of Birmingham Zoning Ordinance (Ord. No. 90-130) governs accessory dwellings in Chapter 1, Article III, Section 9 and Chapter 4, Article IV, Section 2.B. An accessory building may be used for dwelling purposes only when the dwelling conditions are met: only one accessory structure per lot may be used as a dwelling, access must be from an alley or an approved driveway, and the accessory dwelling must be accessory to a single-family dwelling, Historic Bed and Breakfast, or Bed and Breakfast use. Although accessory buildings generally may not occupy more than 30 percent of the required rear yard, an Accessory Dwelling Unit may cover more than 30 percent provided it is no more than 800 square feet (or the size of the primary dwelling, whichever is less) and meets the Design Standards defined elsewhere in the Ordinance. Permitted districts for an accessory dwelling are D-4, D-5, UN, MU-L, MU-M, MU-H, MU-D, C-1, and C-2.